1. Field of the Invention
The present invention relates to a construction machine equipped with an exhaust gas purifying device.
2. Background Art
Heretofore, there has been known an exhaust gas purifying device designed to be installed in an exhaust pipe of a diesel engine. One example of such an exhaust gas purifying device is disclosed, for example, in JP 3073380B. An exhaust gas purifying device disclosed in the JP 3073380B comprises a DPF (Diesel Particulate Filter) which is an exhaust gas filter for trapping particulate matter, i.e., soot, contained in diesel exhaust gas. Generally, this type of exhaust gas purifying device is configured to regenerate the DPF as required. The regeneration of the DPF is performed by burning particulate matter accumulated in the DPF. The burning of the particulate matter is induced by loading an engine (imposing a certain load on an engine) to raise an exhaust temperature (exhaust gas temperature) of the engine.
Meanwhile, heretofore, there has been known a construction machine equipped with an actuator (hydraulic actuator) adapted to be operated by using an engine as a driving source. This type of construction machine comprises a pump configured to be driven by an engine, an actuator to which hydraulic oil is supplied from the pump, and an actuator control valve provided in a flow passage between the pump and the actuator to control the operation of the actuator.
Further, there has heretofore been known a construction machine equipped with the above exhaust gas purifying device and the above actuator. In this construction machine, if the actuator is manually controlled, while loading (i.e., imposing a load on) the engine to perform the DPF regeneration, the actuator is likely to be activated suddenly.
The JP 3073380B discloses a technique designed to prevent the sudden actuation of the actuator. For example, claim 2 of the JP 3073380B discloses a technique of performing the DPF regeneration only when the actuator control valve for controlling the actuator is in a neutral position. Further, the technique disclosed in the JP 3073380B is configured such that, if a manipulation lever is manipulated during the DPF regeneration, the DPF regeneration is cancelled. Therefore, this technique is likely to give rise to a situation where, during the DPF regeneration, the regeneration is cancelled, resulting in failing to accomplish the DPF regeneration.
Therefore, JP 2010-059620A proposes a technique designed to satisfy both of prevention of the sudden actuation of the actuator, and accomplishment of the DPF regeneration. Specifically, FIG. 2 of the JP 2010-059620A discloses a technique of disenable an operation of the actuator control valve until the DPF regeneration is completed. In other words, the technique disclosed in the JP 2010-059620A is configured to disenable an operation of the actuator over the entire period from start to end of the DPF regeneration.
However, this technique obliges a user of a construction machine to wait under the condition that the actuator is stopped, until the DPF regeneration is completed. A time required for the DPF regeneration depends on an amount of particulate matter accumulated in the DPF, but the time required for the DPF regeneration is generally in the range of several minutes to several ten minutes. The user of the construction machine cannot perform a work using the actuator during the DPF regeneration. Thus, the user of the construction machine will waste his/her valuable time. On the other hand, if a construction machine is configured to enable manual control of the actuator in parallel with the DPF regeneration, the actuator is likely to be activated suddenly, as mentioned above.